�us cw�� Chris L Peterson:

On Sat, 16 Aug 2008 22:16:27 -0500, Charlie Siegrist
<none.active@this.time.check.back.later> wrote:

On Sat, 16 Aug 2008 19:31:07 +0000, Paul J Gans wrote:

Because the radio age *here* will last only about 200 years, if
that.

I don't see why.  As fiber-optic communication spreads, microwave
point- to-point is tending to decrease, but cell phone and other
personal radio communication devices are proliferating at a strong
rate.

Certainly, there is no reason to think we'll stop using radio. As you
note, its use will increase. But the sort of radio we use will not
make us radio bright. It is reasonable to think that technological
civilizations would only be detectable by their waste radio emission
for a short time. Radio remains an obvious candidate for any
civilization that deliberately wants to make itself known, however.

I thought Paul was alluding to the possible brevity of an 
advanced-technology human civilisation.